It turned out that this is not the case. The 'name' and 'clan' fields are max 32 chars, not fixed at 32 chars.

Then your struct definition is wrong.

If the strings are variable length, then use 'Z*':

print for unpack 'n N Z* C Z* C', 
    "\x01\x01\x04\x03\x02\x01The first string\0\xffThe second string\0
+\xff";;
257
67305985
The first string
255
The second string
255
[download]

That's why I structured the code a bit more than I usually tend to in perl...

I'm not suggesting you stop structuring your code, just structure is differently. Java streams are just one possible abstraction of the problem.

I would suggest a different abstraction that uses the power of unpack format strings. Have a different class for each packet and pass the buffer into the constructor and have it remove its stuff from that buffer.

package This::Packet;

sub new {
    my( $class, $bufRef ) = @_;
    my( $ping, $rate, $name, $ctpos, $clantag, $isbot ) 
        = unpack 'n N Z* C Z* C', $$bufRef;
    my $nPacket = 2 + 4 
        + length( $name )+ 1 + 1      ## string + null + ctpos
        + length( $clantag ) + 1 + 1; ## string + null + IsBot

    # ... validate

    substr( $$bufRef, 0, $nPacket, '' ); ## remove this packet from th
+e buffer
    return bless { 
        ping => $ping,
        rate  => $rate,
        name  => $name,
        cpos => $ctpos,
        clantag => $clantag,
        isBot   => $isBot,
    }, $class;
}

## accessors go here
[download]

This way moves all the packets specific information inside a class that deals with that packet. Each class removes it's data from the buffer and the higher level only has to decide which packet to deal with next.